Sundogs

Definition

Sundogs are bright spots that appear on either side of the sun when it is low on the horizon, caused by the refraction of sunlight through ice crystals in the atmosphere. They are part of a larger category of optical phenomena associated with halos, which are also created by the interaction of light with ice crystals. Sundogs typically appear as two distinct bright spots that can occur simultaneously with halos, creating a visually striking effect in the sky.

5 Must Know Facts For Your Next Test

1. Sundogs are most commonly visible when the sun is at a low angle, typically during sunrise or sunset.
2. They usually occur in pairs, located approximately 22 degrees from either side of the sun, and can appear simultaneously with halos.
3. The formation of sundogs is primarily dependent on the presence of high-altitude cirrus or cirrostratus clouds, which contain ice crystals.
4. Sundogs can be mistaken for sunspots or other atmospheric phenomena but are distinctly characterized by their bright appearance and positioning relative to the sun.
5. The intensity and visibility of sundogs can vary based on atmospheric conditions such as humidity and temperature, making them more prominent in cold weather.

Review Questions

• Explain how sundogs form and what atmospheric conditions contribute to their appearance.
  • Sundogs form when sunlight passes through ice crystals suspended in the atmosphere, typically found in high-altitude cirrus clouds. The ice crystals refract the sunlight at specific angles, producing bright spots on either side of the sun. These phenomena are most often visible when the sun is low in the sky, such as during sunrise or sunset, and require specific atmospheric conditions, including cold temperatures and humidity levels that allow for ice crystal formation.
• Compare and contrast sundogs with halos in terms of their formation and visual characteristics.
  • Sundogs and halos both result from the refraction and reflection of sunlight through ice crystals in the atmosphere. However, sundogs appear as bright spots located approximately 22 degrees from either side of the sun when it is low on the horizon, while halos are larger circles that encompass the sun or moon. While sundogs can occur simultaneously with halos, they are distinct features; sundogs emphasize specific points of light while halos create a continuous band around celestial bodies.
• Evaluate the significance of understanding sundogs within atmospheric physics and its implications for predicting weather patterns.
  • Understanding sundogs is significant within atmospheric physics as they serve as indicators of specific atmospheric conditions that may precede changes in weather. The presence of ice crystals in high-altitude clouds suggests that cold air masses may be nearby, potentially signaling approaching weather systems like precipitation or shifts in temperature. By studying these optical phenomena, meteorologists can improve their predictions about weather patterns and better understand atmospheric dynamics, contributing to more accurate forecasts.

Related terms

Halos: Optical phenomena that appear as circles of light surrounding the sun or moon, formed by the refraction and reflection of light through ice crystals in the atmosphere.

Ice Crystals: Small, solid particles of ice that form in the atmosphere and play a critical role in creating sundogs and halos by refracting and reflecting sunlight.

Atmospheric Refraction: The bending of light as it passes through different layers of the atmosphere, which is essential for the formation of sundogs and other optical phenomena.